Insert Cover jpeg here. Make wrapping “In front of text.” DR. MARK A. SKINNER Dr. Mark A. Skinner is senior project leader in Space Traffic Management at The Aerospace Corporation. He has been involved in space for 40 years, with efforts encompassing high-energy astrophysics, space situational awareness, space debris, satellite characterization, and space traffic management. Skinner has bachelor’s degrees in physics and the humanities and science from the Massachusetts Institute of Technology, an MBA from the International Space University, and a Ph.D. in experimental astrophysics from the University of Wisconsin-Madison. ABOUT THE CENTER FOR SPACE POLICY AND STRATEGY The Center for Space Policy and Strategy is dedicated to shaping the future by providing nonpartisan research and strategic analysis to decisionmakers. The center is part of The Aerospace Corporation, a nonprofit organization that advises the government on complex space enterprise and systems engineering problems. The views expressed in this publication are solely those of the author(s), and do not necessarily reflect those of The Aerospace Corporation, its management, or its customers. Contact us at www.aerospace.org/policy or [email protected] Summary Success in space flight operations is often difficult due to the harsh space environment. Naturally occurring charged particles and other cosmic radiation cause short- and long-term issues with onboard electronics and mechanical mechanisms; extensive amounts of UV light degrade satellite surface treatments; and the extremes of heat and cold challenge satellite designs. Additionally, self-induced issues involving design, construction, testing, launching, and monitoring can result in premature satellite failures, so the odds are stacked against full mission success for many resource-constrained space missions. Of particular concern is the growing number of very small satellites (CubeSats) launched en masse that for a variety of reasons are never identified or brought online because of early on-orbit failure. As the number of massed CubeSat launches rises, and the number of CubeSats per launch increases due to flight opportunities brought about by launch consolidators, the number of CubeSats deployed that are “dead on arrival” (DOA) increases. Beyond the heartbreak this brings to the owner/operator teams, DOA CubeSats violate guidelines and best practices designed to decrease the amount of space debris in orbit.1 This paper investigates the detailed nature of this rather paradoxical problem, in which the inability to identify (ID) a satellite may cause its early demise and a non-functioning CubeSat may be difficult to ID, adding to the confusion. To mitigate this problem, the paper will examine a number of regulatory, systems engineering, and technical solutions involving low-cost means to facilitate identification of CubeSats after launch along with planned flight demonstrations of some of these techniques and technologies. The desired outcome is to outline a practical means to independently identify space objects. Introduction space arena beyond deep-pocketed governments CubeSats, small satellites built around a 10 cm and companies. What previously might have taken building block (i.e., a one unit or “1U” CubeSat is years to develop can now be accomplished in 10 cm x 10 cm x 10 cm, a 2U is 20 cm x 10 cm x months, and for significantly less money. This has 10 cm, etc.), offer affordable access to space. Their allowed educational institutions, down to the middle standardized size and shape have allowed a CubeSat school level, to fly their own CubeSats. It has also industrial ecosystem to flourish, which has lowered allowed numerous developing countries their first costs for acquisition and launch, and vastly satellite. It has allowed more traditional aerospace shortened development times. This has enabled companies and government agencies very rapid access to space for many nontraditional actors in the cycle times for research and development efforts. In 1 short, it has opened up outer space to many more perhaps because of an electronic circuit latch-up or than in the first half-century of the Space Age. Yet due to battery discharge.8 it is those same beneficial characteristics (small, uniform size and shape, low cost for acquisition and This sets up a hazardous paradox wherein: launch, etc.) that have led to a complex technical challenge that is rather unique to CubeSats. This Unidentified satellites cannot be correctly noted 9,10 work addresses this challenge and explores various in catalogs of space objects. solutions: systems engineering techniques, technical Owner/operators cannot be notified of any solutions for independently identifying space conjunction assessments (although given that objects2, and regulatory and policy issues. many CubeSats do now have maneuver It is certainly in no one’s interest to launch satellites capability, this may not be the most important that are dead on arrival to orbit, die shortly after consideration). launch, or cannot be identified and connected to Unidentified satellites cannot be registered with ground support. Internationally agreed to guidelines the United Nations Office of Outer Space Affairs suggest minimizing the launching of debris3; (UNOOSA), thereby impeding a Launching additionally, when an object is launched into space, State from fulfilling Outer Space Treaty it is the responsibility of the Launching State, the obligations.11 State overseeing and supervising the launch, to register the space object.4 How Did We Get to This Situation? If a satellite cannot be identified, it is often very At the start of the Space Age (1950s and early difficult to establish ground-to-space radio 1960s), satellites were small (e.g., Sputnik and communications. This is because the satellite Explorer).12 However, over the decades, more typically has a weak radio signal, and with a narrow- capable launch vehicles enabled satellites to beam ground-station antenna, it can be hard to increase in size, mass, and power and fulfill 5 efficiently search for it. If there are numerous increasingly challenging scientific, commercial, and unidentified satellites from the same launch (e.g., a defense missions. The price to launch into orbit swarm of CubeSats), the owner/operator can try to (dollars per kilogram to orbit) favored the use of establish communications with each satellite in turn, large, expensive launch vehicles.13 Launching a but they are often in close proximity. With only a small payload on a dedicated rocket was usually not few brief passes available to connect with a ground viable or efficient because of the discrepancy station, successful contact might not be established. between the launch vehicle lift capability and the This makes it extremely difficult to establish satellite size and mass. In this case, the cost of the communications and perform early-orbit operations large rocket would eclipse the cost of the satellite. 6,7 vital to the survivability of the satellite. In some When small payloads did need a ride to orbit, they instances, an operator may point the ground station generally went along as a secondary payload. This antenna at a “bunch” of satellites. If they are close is how early CubeSats got to space. Small satellites enough to each other, the operator might get lucky as secondary payloads were sometimes “dropped and communicate blindly with the correct satellite. off” along the way to the primary payload’s orbit or However, luck should not be a strategy. Extensive they rode along to the final orbit position with the searching consumes time and resources. During this primary payload. In either case, it usually was not time, the satellite might fail before it is identified, difficult to distinguish between primary and 2 secondary payloads via size and operational and cost reasons, the CubeSats are generally parameters. launched into very similar orbits over a short time period. Such batch launches are what gave rise to The situation changed as consolidators began “CubeSat confusion.” By launching CubeSats with bundling CubeSats and other smaller payloads low spatial separation, they become hard to together with larger payloads.14,15,16 Ride sharing distinguish from each other. By launching them with helped fill the excess capacity of many launch low temporal separation, existing space situational vehicles and enabled more cost-effective launches awareness (SSA)/space traffic management (STM) for small satellites. Eventually, consolidators began systems21 do not have time to react to the addition buying up entire launch vehicle manifests, and of so many new space objects all at once.22,23,24 As reselling the ride to a large number of CubeSats. In Figure 1 shows, it can take weeks or months to these cases, there was no longer a primary, large identify objects (and some may never be uniquely payload, as the entire capacity was filled with small identified at all).25 Note that this scenario is not satellites. As microsatellite size envelopes became generally realized for launches consisting mainly of standardized with the advent of CubeSats, a berth on one company’s satellites (e.g, SpaceX StarLink or a rocket became fungible17; if any given CubeSat Planet constellations) because the company will with a reservation on a launch manifest fell behind have the ability to communicate with their own schedule, that reservation could be traded to a satellites, can determine via telemetry the CubeSat that was ready to go. CubeSats enabled an identification (ID) of each one, and generally have economy of scale, both for production and for an established relationship with SSA/STM systems launch, which further decreased total mission costs. that can help resolve discrepancies in identifying their satellites. Additionally, large batches of Thus, we now have the situation where various commercial satellites launched in constellations are capable launch vehicles (such as SpaceX, Rocket fully functional production class rather than Labs, Polar Satellite Launch Vehicle (PSLV)) are experimental satellites with limited capabilities. manifested solely with large numbers of CubeSats 18,19,20 coordinated by consolidators.